Spatial economic predictions of managed aquifer recharge for an agricultural landscape

Abstract

Groundwater banking through managed aquifer recharge (MAR) can augment the irrigation water supply with less social and environmental opposition than dams. Our high spatial resolution hydro-economic model investigates the influence of site conditions such as natural recharge, proximity to surface water sources, and the agronomic conditions of crops on four model outcomes: optimal MAR, final groundwater level, present value of farm net returns, and the cost-effectiveness of a MAR subsidy. We find that less irrigation intensive crops are a substitute for MAR while rice and dryland crops are a complement for MAR. Optimal MAR is larger at a site with greater net returns to rice and dryland soybeans, lower net returns to irrigated corn and soybeans, and lower natural recharge. MAR increases groundwater conservation most at the sites with higher net returns to dryland and irrigated soybeans and lower net returns to corn and cotton. MAR raises the present value of economic returns from agriculture more where the net returns from rice are large, but the cost-effective locations for a MAR subsidy are sites with large net returns to crops like cotton and soybeans. Higher natural recharge at a site correlates with a lower present value of economic returns from MAR and a less cost-effective MAR subsidy.